WSP08458 - Laserfiche WebLink

Home Browse Search

- tT1 'f' ~ IV Table ES-l, Summary of Potential Impacts of the Execution of the lA, Adoption of the lOP, and Implementation of Biological Conservation Measures (Poge 3 of 29) '" ~ " g - ;:;. " ~ 3 " " << tl '" ..... 'J> I ResoLlrce/lsslle No Acti011 Impacts of Proposed Actiol//Altematives HYDROLOGYIW A TER QUAlITYIW A TER SUrPL Y Potential impacts lu Colorado River flows from Without passage of the 101', the Secretary would be Proposed 101': With implementation of the 101', the inadvertent overruns and payback policy. required to enforce the provisions of the Decree. average increase in annual flow during overruns in The Secretary would continue with the existing the Hoover-Io Parker River reach would be policy of not delivering water in excess of a State's, approximately 90 KAF. An increase of 90 KAF to water district's, or entity's entitlement. No impact annual flow represents an increase from historic on now. average annual flows of 0.8 percent and an increase over flows under No Action as great as 1.1 percentl. The average decrease in flow due to paybacks would be roughly 72 KAF, or 0.6 percenlless than average annual historic flows and 0.8 percent less than under No Action. Assuming the worst-cilse scenario, annual flows from Hpover Dam 10 Parker Dam could be augmenled by overruns by as much as 313 KAF and diminished by payback as great as 206 KAF. However, these represent the most extreme possible annual flow changes. With implementation of the lOP, the average increase in annual flow in the Parker to Imperial River reach would be approximalely 90 KAf. An increase of 90 KAf to annual flow represents an increase from historic average annual flows of 0.9 percent and an increase over flows under No Action ~s greal as 1.3 percent2. The average decrease in flow would be roughly 63 KAF, or 0.7 percent less than average annual historic flows and 0.9 percent less than under No Action. Assuming the worst- case scenario, annual flows below Parker Dam could be augmented by overruns by as much as 313 KAF and diminished by payback as gre.,t as 176 KAF. However, these represent the most extreme possible .mnual flow changes. - " :! ~ << N '" '" N ..... i"- ..... o ,'1:1 " ~ ... ~ '" ;;- ~ " ... ~ ... '" , " ;.. ~ - o. ~ ~ '" ..... <J> I 2 Increased and dl'crl:'aseJ flows resulting from implementation of Ihe lOP were compared to estimated nows under No Action at f-Iavasu National NWR. Increased and decreased flows resulting from implementation of the lOP were compared to estimated flows under No Action at I-Ieadgate Rock Dam. - - ., -- - - - - - - 11II - - - - lID